1. Field of the Invention
This invention relates computer hardware security and, more particularly, to an apparatus for selectively securing an externally accessible circuit card within a computing system or other electronic device.
2. Summary of the Background Art
As data becomes increasingly available in encoded formats that require an electronic device, such as a computing system, to make the data visible and usable, there is an increasing need for various organizations to make such devices publicly available under certain conditions. For example, libraries frequently provide computing systems for use by the public within the library to aid in finding and displaying information as required. A library may wish to make laptop systems available in this way in order to provide convenience of use and further to avoid the dedicated space requirements associated with the use of desktop computers.
One problem with making laptop computers publicly available in this way arises from the fact that, while the computers themselves are large enough to make their theft difficult, externally accessible cards, known as PC Cards, are small enough to be easily concealed and stolen. Such cards are often needed to provide a laptop computer with functions needed within such an environment, such as an ability to connect to a wired or wireless network.
PC Cards are built according to the standards of the PCMCIA (Personal Computer Memory Card International Association) to fit into slots that are now widely available on laptop computers, and to provide various functions that are not generally provided within the computers themselves, such as connection to networks. The slots are externally accessible, with the cards being readily installed and removed. Since the cards are the length and width of a credit card, with variations in overall thickness as provided by the PCMCIA standards, these cards are easily concealed and stolen. On the other hand, much of the usefulness of PC Cards arises from the fact that they can be easily removed and used in another standard computer, with the card mounting structures and connectors associated with the sockets being built to widely used standards.
Nonvolatile memory can also be added to a number of laptop computers and other electronic devices by installing removable cards having either the PC Card configuration or a somewhat different Compact Flash Card shape.
Therefore, what is needed is a way to make small, externally accessible circuit cards selectively difficult to remove, so that they cannot be easily stolen, while allowing the easy removal and replacement of the cards by personnel of the organization owning the cards and the computing systems.
In early personal computing systems, circuit cards and other optional small devices were held within the covers of the computer, with conventional locking mechanisms, having cylinders turned by keys, holding the covers shut to protect the devices inside. U.S. Pat. No. 5,169,332 describes apparatus protecting external devices, such as a cable connector, a terminator, or a shield covering a port connector from unauthorized removal by making the devices removable only through access within the locked covers of a computing system.
A number of other patents describe the use of additional conventional locks to prevent the removal of devices from computers and other electronic systems, or to prevent access to various parts of the systems. For example, U.S. Pat. No. 5,190,465 describes cover assemblies, fastened in place by conventional locks, for preventing the removal of an external cable from a computer. U.S. Pat. Nos. 4,655,057 and 4,964,286 describe the use of locking covers to prevent access to the slot in which a videocassette is inserted within a videocassette recorder. U.S. Pat. No. 4,685,312 describes the use of a locking device to prevent access to the slot through which removable media is inserted into a computer disk drive unit.
As some computing systems, such as laptop computers, became smaller and more portable, some of the functions provided by relatively large cards housed within the computing systems were assigned to the small, removable and interchangeable PC Cards. Again, what is needed is a way to prevent the unauthorized removal of such cards, preferably without requiring the use of bulky covers having locking cylinders and further without requiring modification to a conventional computer having provisions for using such cards.
Other patents describe methods for mounting printed circuit boards within electronic devices without addressing a means to provide for selective removal, requiring possession of a key, to prevent theft. For example, U.S. Pat. No. 6,424,542 describes a PC Card holder mounted on a circuit board, with a card retainer being mounted adjacent to the holder to prevent unintentional movement of the card out of an engaged position when the holder is subjected to vibrations. The retainer preferably includes a finger having a hook formed on a free end thereof that is yieldably biased into a position in which it blocks the unintended movement. When the card is being intentionally removed from the holder, movement of the card deflects the finger to allow passage of the card. U.S. Pat. No. 4,096,548 describes a circuit board that is retained in a fixed position within a rack frame by a leaf spring, flexibly mounted on the circuit board, which has a detent portion engageable in a recess in the rack frame. A rod mounted on the circuit board by a bracket is operable to engage the leaf spring and to move the detent portion into and out of engagement with the recess. U.S. Pat. No. 6,373,713 describes a mechanism for inserting, extracting, sensing, and locking a printed circuit board assembly in an electronic system with a single handle.
U.S. Pat. No. 6,269,005 describes the use of a pair of flexible arms having projections extending outward into slots within a PC Card retainer to hold a dummy card in a space within such a retainer, which has been configured for a relatively thick Type III card, above a relatively thin Type I or II card. The dummy card blocks an air passage that might otherwise allow dirt and dust to enter the computer.
Accordingly, it is a first objective of the invention to provide a means for preventing the removal of a circuit card from an electronic device without the use of a key.
It is a second objective of the invention to provide a means for allowing the easy removal and insertion of the circuit with the use of a key.
It is a third objective of the invention to provide a means for selective removal of a card from a standard PC Card slot without a need to modify the slot.
In accordance with a first aspect of the invention, circuit card apparatus selectively removable from a card receptacle is provided. The circuit card apparatus includes a circuit board, guiding surfaces, a key receptacle, a key, and a first braking member. The guiding surfaces are attached to the circuit board for guiding the circuit board into the card receptacle. The key is removably insertable within the key receptacle. The first braking member is movably mounted within the circuit card apparatus. The first braking member is held in an extended position, extending outward to contact the card receptacle, with the key removed from the key receptacle. The first braking member is held in a retracted position, displaced inward from the extended position, when the key is fully inserted in the key receptacle.